1. Field of the Invention
The tool changer of the present invention relates to a device for rapidly and conveniently changing a tool holder in a milling machine.
2. Description of the Prior Art
Conventional vertical milling machines incorporate a draw bar suspending a collet from the lower end thereof for radially gripping the shank of a working tool and are formed with a male tightening taper formed in the spindle upon retraction of such draw bar to center such collect and shank, as illustrated in U.S. Pat. No. 3,651,739 to Wolf. In the past, the collet was actuated either manually, by fluid pressure, as shown in U.S. Pat. Nos. 3,651,739 to Wolf, or 3,678,801 to Hague et al, and in similar structure by mechanical toggle locking devices such as that shown in U.S. Pat. No. 1,871,463 to Olson.
However, such prior art collet actuating devices were either laborious and time-consuming, such as the manually operated devices, expensive pieces of equipment, such as the fluid pressure devices, or inadequate for the desired application, such as the toggle locking devices. The present invention satisfies the need for a fast and economical draw bar actuating device for a machine tool.